Seedhead of Tussilago farfara. Coltsfoot.

This could be mistaken for a dandelion, but there are some obvious differences.

The seedhead is flatter than that of a dandelion.

The stem bears scale-leaves in early spring, whereas the stem of a dandelion is smooth.

The leaves appear after the flowers have gone to seed and are shaped like a horse shoe, hence the common name. The leaves of a dandelion resemble lion's teeth, hence the common name 'dandelion' from the French 'dent de lion'.